A sequence encoding a maturase-related protein in a group II intron of a plant mitochondrial nad1 gene.
We have determined from nucleotide sequence analysis that the subterminal and terminal exons of a respiratory chain NADH dehydrogenase subunit I gene in broad bean mitochondrial DNA (mtDNA) are separated by a group II intron. Within this intron is a 687-codon open reading frame that, from considerations of similarity between amino acid sequences predicted from this open reading frame and maturase-coding sequences in group II introns of certain fungal mitochondrial genes, appears to encode a maturase-related protein. Transcripts complementary to this broad bean sequence (designated a mat-r gene) were detected among RNAs isolated from broad bean mitochondria. Data obtained from DNA-DNA hybridizations indicated that soybean and corn mtDNAs also contain a mat-r gene and suggested that only one copy of this gene occurs in each plant mtDNA. The putative protein specified by the broad bean mat-r gene contains amino acid sequences characteristic of reverse transcriptases. Because of this, consideration is given to the possibility that the maturase-related protein may be functional in the mechanisms by which plant mtDNA sequences are rearranged and foreign sequences are incorporated into plant mtDNAs.
Wahleithner
J A
JA
Department of Biology, University of Utah, Salt Lake City 84112.
MacFarlane
J L
JL
Wolstenholme
D R
DR
D000595:Amino Acid Sequence; D001483:Base Sequence; D015152:Blotting, Northern; D004272:DNA, Mitochondrial / Q000235:genetics*; D005091:Exons; D007887:Fabaceae / Q000201:enzymology / Q000235:genetics*; D017343:Genes, Plant; D007438:Introns; D008928:Mitochondria / Q000201:enzymology*; D008969:Molecular Sequence Data; D009245:NADH Dehydrogenase / Q000235:genetics; D009690:Nucleic Acid Conformation; D010940:Plant Proteins / Q000235:genetics*; D010946:Plants, Medicinal; D015183:Restriction Mapping; D012689:Sequence Homology, Nucleic Acid
D004272:DNA, Mitochondrial; D010940:Plant Proteins; D009245:NADH Dehydrogenase